CHAPTER ONE THE SCIENCE OF BIOLOGY

Chapter 1 – The Science of Biology Biology is the study of living things Living things are diverse There are enough similarities among some living things that they can be grouped into the same kingdom Members of different kingdoms are usually very different from each other

KINGDOMS Life on planet Earth is broken down into six groups called Kingdoms. Bacteria Archaea Protista Fungi Plantae Animalia BACTERIAEUKARYA Bacteria Archaea Protista PlantaeFungi Animalia ARCHAEA

4 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Archaea. This kingdom of prokaryotes (the simplest of cells that do not have nuclei) includes this methanogen, which manufactures methane as a result of its metabolic activity. Animalia. Organisms in this kingdom are nonphotosynthetic multicellular organisms that digest their food internally, such as this ram. Protista. Most of the unicellular eukaryotes (those whose cells contain a nucleus) are grouped into this kingdom, and so are the multicellular algae pictured here. Fungi. This kingdom contains nonphotosynthetic organisms, mostly multicellular, that digest their food externally, such as these mushrooms. Bacteria. This group is the second of the two prokaryotic kingdoms. Shown here are purple sulfur bacteria, which are able to convert light energy into chemical energy. Plantae. This kingdom contains photosynthetic multicellular organisms that are terrestrial, such as the flowering plant pictured here. (Achaea): © R. Robinson/Visuals Unlimited; (bacteria): © Alfred Pasieka/Science Photo Library/Photo Researchers; (protista, plantae): © Corbis RF; (fungi, animalia): © Getty RF

DIVERSITY OF LIFE The living world is very diverse – many different types of living organisms – but all living things share many key properties.

PROPERTIES OF LIFE What does it mean to be alive? Complexity (computers are complex) Movement (clouds, ocean waves move) Response to stimulation (soap bubble pops if touched) Let ’ s look at five more properties of life:

PROPERTIES OF LIFE Cellular Organization – All living things are composed of one or more cells. Cell – tiny compartment surrounded by a membrane. Cells may have simple or complex interiors. All can grow and reproduce.

PROPERTIES OF LIFE Metabolism – All living things use energy. Energy comes from the sun. Energy is captured by plants and algae. Plants turn energy from the sun into a form that can be used by the plants and by organisms that eat the plants. The chemical process that extracts energy from a food source is called metabolism.

PROPERTIES OF LIFE Homeostasis – All living things maintain stable internal conditions. Environment is variable. Organisms keep interior relatively constant – homeostasis. Body temperature is one example.

PROPERTIES OF LIFE Reproduction – All living things reproduce. The simplest organisms (bacteria) simply split in two. More complex organisms have more complicated forms of reproduction.

PROPERTIES OF LIFE Heredity – All organisms possess a genetic system that is based on the replication and duplication of a long molecule called DNA (deoxyribonucleic acid). The order of the subunits that make up DNA provide the information needed to determine what an organism will be like.

PROPERTIES OF LIFE Each set of instructions within the DNA is called a gene. Transmission of characteristics from parent to offspring is a process called heredity.

THE ORGANIZATION OF LIFE Organisms function and interact with each other on many levels. Hierarchy of increasing complexity Within cells Within multicellular organisms Among organisms

FIG. 1.4LEFT-1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 Atoms (Hydrogen, carbon, nitrogen) CELLULAR LEVEL

FIG. 1.4LEFT-2 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 2 Molecule (Adenine) Atoms (Hydrogen, carbon, nitrogen) CELLULAR LEVEL

FIG. 1.4LEFT-3 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 2 Molecule (Adenine) Atoms (Hydrogen, carbon, nitrogen) CELLULARLEVEL 3 Macromolecule (DNA)

FIG. 1.4LEFT-4 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Organelle (Nucleus) Molecule (Adenine) Atoms (Hydrogen, carbon, nitrogen) CELLULARLEVEL 3 Macromolecule (DNA)

FIG. 1.4LEFT-5 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Organelle (Nucleus) Molecule (Adenine) Atoms (Hydrogen, carbon, nitrogen) CELLULARLEVEL 3 Macromolecule (DNA) 5 Cell (Nervecell)

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Organelle (Nucleus) Molecule (Adenine) Atoms (Hydrogen, carbon, nitrogen) ORGANISMAL LEVEL CELLULARLEVEL 3 Macromolecule (DNA) 5 Cell (Nervecell) 6 Tissue (Nerve tissue)

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Organelle (Nucleus) Molecule (Adenine) Atoms (Hydrogen, carbon, nitrogen) ORGANISMAL LEVEL CELLULARLEVEL 3 Macromolecule (DNA) 5 Cell (Nervecell) 6 Tissue (Nerve tissue) 7 Organ (Brain)

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Organelle (Nucleus) Molecule (Adenine) Atoms (Hydrogen, carbon, nitrogen) ORGANISMAL LEVEL CELLULARLEVEL 3 Macromolecule (DNA) 5 Cell (Nervecell) 6 Tissue (Nerve tissue) 7 8 Organ (Brain) Organ system (Nervous system)

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Organelle (Nucleus) Molecule (Adenine) Atoms (Hydrogen, carbon, nitrogen) ORGANISMAL LEVEL CELLULARLEVEL 3 Macromolecule (DNA) 5 Cell (Nervecell) 6 Tissue (Nerve tissue) Organ (Brain) Organ system (Nervous system) Organism

FIG. 1.4RIGHT-1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. POPULATIONAL LEVEL (goose & crane): © Jim Bailey; (geese on lake): © Raymond Gehman/Corbis; (cranes on lake): © Corbis RF; (ecosystem): © Winfried Wisniewski/zefa/Corbis

FIG. 1.4RIGHT-2 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. POPULATIONAL LEVEL Population Species (goose & crane): © Jim Bailey; (geese on lake): © Raymond Gehman/Corbis; (cranes on lake): © Corbis RF; (ecosystem): © Winfried Wisniewski/zefa/Corbis

FIG. 1.4RIGHT-3 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. POPULATIONAL LEVEL Community Population Species (goose & crane): © Jim Bailey; (geese on lake): © Raymond Gehman/Corbis; (cranes on lake): © Corbis RF; (ecosystem): © Winfried Wisniewski/zefa/Corbis

FIG. 1.4RIGHT Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. POPULATIONAL LEVEL EcosystemCommunity Population Species (goose & crane): © Jim Bailey; (geese on lake): © Raymond Gehman/Corbis; (cranes on lake): © Corbis RF; (ecosystem): © Winfried Wisniewski/zefa/Corbis

ORGANIZATION OF LIFE At higher levels of the living hierarchy, new properties become apparent that were absent at the lower levels These emergent properties result from the interaction of diverse but simpler components Many higher order processes that are hallmarks of life are emergent properties metabolism consciousness

BIOLOGICAL THEMES Evolution – The change in species over time. Charles Darwin proposed the mechanism by which this change takes place – natural selection. Organisms that are better able to respond to challenges in the environment are more likely to survive, reproduce, and pass on their genes to the next generation.

EVOLUTION Artificial Selection Darwin was familiar with variation in domestic animals and that breeders select animals with desired characteristics and breed them to obtain offspring with the desired or exaggerated characteristics.

EVOLUTION The characteristics selected are passed on through the generations because DNA is transmitted from parent to offspring. Darwin extended the idea of artificial selection to the natural world. Thus, the many forms of life we see today reflect a long history of natural selection.

BIOLOGICAL THEMES The flow of energy – All organisms require energy for the activities of living. All of the energy used by most organisms originally comes from the sun. This energy gets used up as it passes through an ecosystem.

THE FLOW OF ENERGY Green plants and photosynthetic protists (algae, seaweed) capture energy from the sun using a process called photosynthesis. Plants serve as the energy source for the animals who eat them.

THE FLOW OF ENERGY Other animals eat the plant-eaters. At each stage, some energy is used, some is transformed, and much is lost.

THE FLOW OF ENERGY The flow of energy is very important in shaping ecosystems: What kind of organisms live there? How many of each?

BIOLOGICAL THEMES Cooperation has played a critical role in the evolution of life on Earth. Coevolution of insects & flowering plants Fungi helped plants first invade land from the sea. Barnacles living on gray whales are carried around exposing them to fresh supply of food.

BIOLOGICAL THEMES Structure determines function – At every level of organization, structures are well suited to their functions.

BIOLOGICAL THEMES Homeostasis – maintaining a relatively constant internal environment is essential for complex organisms. Body temperature Ph Water balance

THE NATURE OF SCIENCE Science is a particular way of investigating the world.

DEDUCTIVE REASONING Deductive reasoning involves making individual decisions by applying accepted general principles. Math Philosophy Politics Ethics DEDUCTIVE REASONING An Accepted General Principle DEDUCTIVE REASONING Traveling at the speed limit, you approach each Intersection anticipating that the red light will turn green as your each the intersection. Using a General Principle to Make Everyday Decisions When traffic lights along city streets are "timed“ to change at the time interval it takes traffic to pass between them, the result will be a smooth flow of traffic.

THE NATURE OF SCIENCE Where do these general principles come from? Religious & ethical principles may have a religious foundation. Political principles reflect social systems. Some general principles come from observing the world around us. Science is based on this type of general principle

INDUCTIVE REASONING Science is devoted to discovering general principles that govern the operation of the physical world. Discovering general principles by careful examination of specific cases is called inductive reasoning. Observations of Specific Events INDUCTIVE REASONING Maintaining the same speed, you observe the same event at the next several intersections: the traffic lights turn green just as you approach the intersections. When you speed up, however, the light doesn't change until after you reach the intersection. You conclude that the traffic lights along this street are "timed“ to change in the time it takes your car, traveling at the speed limit, to traverse the distance between them. Driving down the street at the speed limit, you observe that the red traffic light turns green just as you approach the intersection. INDUCTIVE REASONING Formation of a General Principle

INDUCTIVE REASONING 400 years ago Isaac Newton, Francis Bacon, and others began conducting experiments and inferring general principles about how the world works from their results. Simple observations (such as Newton ’ s apple) are very important in science.

INDUCTIVE REASONING Newton started by simply dropping an apple from his hand. He then performed other simple experiments. Using his results, Newton inferred that all objects fall toward the center of the Earth. This is a hypothesis about how the world works.

INDUCTIVE REASONING Today, scientists still formulate hypotheses to explain how the world works. Observations are the materials that they use to build their hypotheses.

HOW SCIENCE IS DONE Scientists start by making observations concerning a particular problem. A hypothesis is then formed. Hypothesis – a proposition that might be true, an educated guess. Experiments are performed to eliminate alternate hypotheses.

HOW SCIENCE IS DONE Hypotheses that are not rejected are retained because they fit known facts. Hypotheses are often revised or replaced as new data become available. Hypotheses that are well supported by many experiments over time are known as theories.

01.04 Scientific Method Slide number: 2 Observation Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

01.04 Scientific Method Slide number: 3 Question Observation Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

01.04 Scientific Method Slide number: 4 Question Observation Hypothesis 1 Hypothesis 2 Hypothesis 3 Hypothesis 4 Hypothesis 5 Potential hypotheses Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

01.04 Scientific Method Slide number: 5 Question Observation Experiment Hypothesis 1 Hypothesis 2 Hypothesis 3 Hypothesis 4 Hypothesis 5 Potential hypotheses Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

01.04 Scientific Method Slide number: 6 Question Observation Reject hypotheses 1 and 4 Experiment Hypothesis 1 Hypothesis 2 Hypothesis 3 Hypothesis 4 Hypothesis 5 Potential hypotheses Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

01.04 Scientific Method Slide number: 7 Question Observation Reject hypotheses 1 and 4 Experiment Hypothesis 5 Hypothesis 3 Hypothesis 2 Remaining possible hypotheses Hypothesis 1 Hypothesis 2 Hypothesis 3 Hypothesis 4 Hypothesis 5 Potential hypotheses Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

01.04 Scientific Method Slide number: 8 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Question Observation Reject hypotheses 1 and 4 Experiment Hypothesis 5 Hypothesis 3 Hypothesis 2 Remaining possible hypotheses Hypothesis 1 Hypothesis 2 Hypothesis 3 Hypothesis 4 Hypothesis 5 Potential hypotheses

Reject hypotheses 2 and Scientific Method Slide number: 9 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Question Observation Reject hypotheses 1 and 4 Experiment Hypothesis 5 Hypothesis 3 Hypothesis 2 Remaining possible hypotheses Hypothesis 1 Hypothesis 2 Hypothesis 3 Hypothesis 4 Hypothesis 5 Potential hypotheses

Reject hypotheses 2 and Scientific Method Slide number: 10 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Question Observation Reject hypotheses 1 and 4 Experiment Hypothesis 5 Hypothesis 3 Hypothesis 2 Remaining possible hypotheses Last remaining possible hypothesis Hypothesis 5 Hypothesis 1 Hypothesis 2 Hypothesis 3 Hypothesis 4 Hypothesis 5 Potential hypotheses

Reject hypotheses 2 and Scientific Method Slide number: 11 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Question Observation Reject hypotheses 1 and 4 Experiment Hypothesis 5 Hypothesis 3 Hypothesis 2 Remaining possible hypotheses Last remaining possible hypothesis Hypothesis 5 Predictions Experiment 1Experiment 2Experiment 3Experiment 4 Predictions confirmed Hypothesis 1 Hypothesis 2 Hypothesis 3 Hypothesis 4 Hypothesis 5 Potential hypotheses

THE SCIENTIFIC PROCESS Scientific investigations can be broken down into six stages.

OBSERVATION Observation is the key to any successful scientific investigation. Scientists take note of many details and keep careful records of these details.

OBSERVATION - SCIENCE IN ACTION: A CASE STUDY Example – Scientists in the Antarctic kept careful record of temperature, light and levels of chemicals. They realized the level of ozone was dropping.

HYPOTHESIS A hypothesis is a guess that might be true – a potential explanation for the observations that have been made. Antarctic scientists guessed that CFCs may be responsible for ozone depletion. Chlorine from the CFCs reacts with O 3 producing O 2.

HYPOTHESIS Scientists form several alternate hypotheses when they have more than one guess about what they observe.

PREDICTIONS If a hypothesis is correct, several consequences might be predicted. Prediction – what you would expect to happen if a hypothesis is true.

PREDICTIONS If the CFC hypothesis is true, it should be possible to detect CFCs in the upper Antarctic atmosphere as well as the chlorine released from CFCs that attack the ozone.

TESTING The next step is to verify the prediction. A test of a hypothesis is an experiment.

TESTING To test the CFC hypothesis, atmospheric samples were collected 6 miles over the Antarctic. CFCs were found as predicted. Free chlorine & fluorine were also found confirming breakdown of CFCs. These results support the hypothesis.

CONTROLS A factor that might influence a process that we are interested in is called a variable. To evaluate alternative hypotheses about one variable, all others must be held constant so that we are not misled.

CONTROLS Carry out 2 experiments in parallel: In one, a variable is altered in a known way to test a particular hypothesis. In the other, the variable is not altered. This is called a control experiment. The two experiments are identical in every way except for the one variable under consideration.

CONTROLS In our example, scientists set up experiments reconstructing conditions in the upper atmosphere. In one set-up they added CFCs. In the other they added no CFCs. Ozone levels only dropped in the set-up containing the added CFCs.

CONCLUSION A hypothesis that has been tested and not rejected is tentatively accepted. A collection of related hypotheses that have been tested many times is called a theory.

CONCLUSION The hypothesis that CFCs released into the atmosphere are destroying the Earth ’ s protective ozone shield is now supported by a great deal of experimental evidence and is widely accepted as a theory.

THEORY AND CERTAINTY Hypotheses that are often tested and never rejected are sometimes combined into general statements called theories. A Theory is a unifying explanation for a broad range of observations. Theory of gravity Theory of evolution Theory of the atom

THEORY AND CERTAINTY Theories represent the ideas of which scientists are most certain. There is no absolute truth in science, only varying degrees of certainty. It is always possible that new information will surface causing a theory to be revised.

THEORY AND CERTAINTY Very active areas of science are often full of controversy. Not a sign of poor science. Push & pull that is the heart of the scientific process. Example – global warming due to excessive production of CO 2.

The Scientific “ Method ” A scientist does not follow a fixed method to form a hypothesis. Judgment and intuition are also very important to the process of science.

LIMITATIONS OF SCIENCE Scientific study is limited to organisms and processes that we are able to observe and measure. Supernatural and religious phenomena are completely outside the realm of science.

LIMITATIONS OF SCIENCE Science can point us toward solutions to problems only when those solutions exist. Science can not restore extinct animals. Science may not be able to fix all problems created by polluting the environment and using up resources.

FOUR THEORIES UNIFY BIOLOGY AS A SCIENCE 1. The Cell Theory 2. The Gene Theory 3. The Theory of Heredity 4. The Theory of Evolution

THE CELL THEORY: ORGANIZATION OF LIFE Robert Hooke, 1665 Discovered cells Anton van Leeuwenhoek, 1670s Discovered single-celled life Matthias Schleiden & Theodor Schwann, 1839 All living organisms are composed of cells Cells are the basic units of life Later the third tenet of the theory was added All cells come from other cells

Genetic information is encoded in molecules of deoxyribonucleic acid (DNA) Genes can encode specific proteins or RNA, or they can act to regulate other genes The proteins and RNA encoded by an organism ’ s genes determine what it will be like in terms of form and function THE GENE THEORY: MOLECULAR BASIS OF INHERITANCE

FIGURE 1.12 THE GENE THEORY Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display MACROPHAGE NERVE CELL INTESTIONAL CELL Nucleus Chromosomes Genes being used MUSCLE CELL ChromosomeGene DNA double helix Nucleotides All cells contain the same set of genes, but different kinds of cells use different genes.The production of specific proteins coded for by these genes determines what the cell is like. A typical human chromosome can contain up to a thousand genes, arrayed along a linear piece of DNA. Each gene is composed of a sequence of several hundred to many thousands of DNA nucleotides and functions as a discrete unit of information. A human cell has 46 chromosomes, containing some 3 billion nucleotides of DNA. 1 A human body contains over 100 different kinds of cells.

Genes are passed down in generations as discrete units. Mendel ’ s theory of heredity gave rise to the field of genetics. The chromosomal theory of inheritance located Mendelian genes on chromosomes. THE THEORY OF HEREDITY: UNITY OF LIFE

Charles Darwin ’ s theory of evolution explains the unity and diversity of life as “ descent with modification”. Advances in genetics have helped scientists understand precisely how changes in genes can result in adaptation and evolution. THE THEORY OF EVOLUTION: DIVERSITY OF LIFE